But he did confirm that a range of new Prius body styles are on the way, intended to complement Toyota’s third-generation hybrid saloon when it goes on sale late next year.

Fonseca wouldn’t be drawn on what body styles we should expect, but Autocar understands that an estate version is likely and that a hybrid MPV is a possibility.

The production version of the next Prius is due to make its debut at the Detroit motor show in January, before going on sale towards the end of 2009. Any new body styles won’t be revealed until late 2010 at the earliest.

Fonseca quashed rumours that the next Prius would adopt lithium-ion battery technology at some stage of its lifespan.

While he acknowledged that powerful, efficient lithium-ion batteries were a future direction, Toyota’s engineers do not believe they are efficient or durable enough to enter mass-production yet. The new Prius will be faster, larger and more efficient than the current car.

It will use Toyota’s new-generation Hybrid Synergy Drive, coupling longer-lasting batteries and more powerful electric motors with a more efficient 1.5-litre engine.

Rumours suggest the Prius saloon will achieve more than 90mpg. We’ll find out at Detroit in January.